Bottom End Rebuild Pics

[Mark Halligan]

OK I found the job sheet for the latest pistons, all the same other than the fact that each piston lost a further 2gms due to the custom machining options.

[Billman]

Sorry btu i dont get it right what are the positive or negative effects about Lateral gas ports?

What other specs-coatings should the pistons have? My goal is a reliable piston that maybe would not be the best thing but also dont have any thoughts about coatings going bad.

Can you give me some advice here?

I am going for Diesel Block and crank and 158mm 23mm rods.

[Mark Halligan]

Sorry btu i dont get it right what are the positive or negative effects about Lateral gas ports?

What other specs-coatings should the pistons have? My goal is a reliable piston that maybe would not be the best thing but also dont have any thoughts about coatings going bad.

Can you give me some advice here?

I am going for Diesel Block and crank and 158mm 23mm rods.

Gas ports allow combustion pressure to get behind the top compression ring and force the ring out against the bore wall resulting in better ring seal on the compression / power strokes. This gas pressure still gets behind the ring to a lesser degree with normal pistons but the gas ports allow more pressure to get behind the ring and give a more aggressive seal, the down side of this though is accelerated ring and bore wear, (not something I was particularly concerned about with this build).

Piston gas ports come in two flavours vertical or lateral, vertical are used in drag race applications as these engines are usually rebuilt often and carbon doesn't get a chance to block the ports significantly between builds. Lateral ports are usually used in circle track motors.

I am experimenting in using these and so far I am happy with them, although to be fair my lack of time and progress with other areas of the car have prevented me from really giving them some stick.......so far.

Edit
Here is something cut and pasted from the Wiseco site:

Vertical gas ports are primarily used in drag race applications. Lateral gas ports are more often used in circle-track and road-race applications where carbon build up can occur. When gas ports are used, pressure is directed to build up behind the compression ring and seal it against the cylinder wall. This helps prevent ring flutter and extends the power curve upward in the RPM range. Vertical gas ports have the holes drilled from the deck of the piston into the top ring groove and behind the ring. Lateral gas ports are drilled through the bottom side of the top land and extend to the back wall of the ring groove.


And something from JE showing them with other custom piston machining options

http://www.racetep.com/carpics/jeoptions.jpg

HTH cheers

P.S.

My pistons are not coated

[S2central.net]

@MArk - you know too much !

SO jealous of that build of yours - but I'm so glad you are blazing a derisked trail for others less brave to follow. Brilliant thread this.


Paul

[prosty]

Absolutely awesome project! I wish I had the energy to take this many photographs each time I rebuild an engine. Really good work!!

[caterpillar]

what price does one set of 5 of JE custom order go on??? 1500$ or less??? more??

[Jay]

Approx 1500 US$, depends on spec (that would be nearly all boxs ticked regards extras, funny how i know this:mischeif: )

Give Aelred a shout as he is puttng in an order so may be get a bit of discount

Jay

[Jamo]

You can get a set of Wiseco for $800 and you can get a set of 034 JE for $900

[caterpillar]

034 or other DOES NOT have the right piston spec, have a custom crank, and custom conrod...... and a diesel 2,5tdi block,so it has to be custom pistons too....

[Jamo]

034 or other DOES NOT have the right piston spec, have a custom crank, and custom conrod...... and a diesel 2,5tdi block,so it has to be custom pistons too....

Erm email them, Javad does them to any spec but they have a 3 week lead time.

[S4quattro]

I'd like to know how S4quattro got on with his problem too.

Sorry for late reply..

My problem with the engine had nothing too with the TS pistonrings. The pistons was totaly destoyed by knock and detonations.
So it was my own fault the engine "died", trying too run it on a map that wasent suited for that engine. Had MTM 420 map and fuel delivery , but that wasent good enough.

I took me almost 10 months too get new pistons, so in the meanwhile i run the car with the "standard" MTM 420 kit that the car had from new.
Will try too rebuild that engine again (2,5L project) this winter.

[lini]

What is the purpose of the main bearing gridle? Beginer kill me!

[Jamo]

Thanks

Good point - I forgot to mention that the subframe needed modding to clear the sump which is 10mm lower, I did this a long time ago when I knew I would probably use the girdle. Modding the sump is another option too.

Reason for the Zetec headstuds is for the extra length needed with the girdle.

Paint is Blue smooth Hammerite

Cheers

Hey Mark, Could you tell me how did you modded the subframe to sit 10mm lower please?

[Mark Halligan]

I cut out the the top half of the subframe centre piece that sit runs (east/west) under the sump and welded in a new piece that gave the clearance I needed.

[Rocco]

Mark thank you for all the info and your great knowledge

very interesting your thread